> I'm running Networker 7.2 on a Linux workstation (RHEL 3, kernel 2.4.29)
> with a Qualstar 5433 tape library containing two S-AIT drives.
> 
> When I try to clone a saveset on a tape with multiple multiplexed files the
> job proceeds at less 1 MB/sec. At this rate it would take about a week to
> clone one tape.
> 
> If I try to clone one of my archive tapes, where the savesets are not
> multiplexed on the tape, the job proceeds at closer to 40MB/sec.
> 
> Note that for backups parallelism on the tape devices is set to four, so the
> degree of multiplexing is fairly low.
> 
> Any ideas on how to speed things up?

I'd start poking at the clone process with something like truss/strace
(is it generally waiting on reads or writes?) and peek at the I/O rates
on the drives (is the source drive at least delivering expected rates?)

I might also try to clone to a disk device.  If that goes fast, then
it's not as simple as the read speed from the source.   It could be
something complex with the tape drivers...

I've not really seen clone speeds that were drastically slow, so I don't
have any good ideas off the top of my head.

-- 
Darren Dunham                                           ddunham AT taos DOT com
Senior Technical Consultant         TAOS            http://www.taos.com/
Got some Dr Pepper?                           San Francisco, CA bay area
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